In a report published in the Journal of Management last month, researchers from the U.S.'s Florida State University, Old Dominion University, Clemson University and Accenture said that companies should be "very cautious" about using information found on social media to assess candidates.

The researchers asked 86 recruiters to assess the Facebook profiles of 416 undergraduate and graduate students from a large university in the southeastern U.S. They followed up with the applicants a year later and asked their new supervisors to review their performance.

Onathan Nackstrand | AFP | Getty Images

Their findings: recruiters' assessment of information on Facebook was unrelated to a supervisor's ratings of job performance, turnover intentions and actual turnover. Also, the Facebook ratings did not contribute to predicting these factors beyond other more traditional indicators, while there was some evidence in the Facebook ratings that tended to favor female and White applicants.

"In sum, although SM [social media] platforms such as Facebook and Twitter may contain some potentially job-relevant information, identifying and accurately rating this information could be quite difficult," the research said.

"Indeed, such platforms are not designed to elicit job-relevant information and, in fact, contain various types of job-irrelevant information that could influence judgments about applicants."

Social recruiting

Still, there is some evidence that an increasing number of employers are using social media when assessing job applicants. Part of that may be associated with the rise of LinkedIn as a networking site for professionals.

An online survey by recruiting platform Jobvite last year found that 94 percent of recruiters used social networks or social media to support recruitment efforts in 2013, up from 89 percent in 2011 and 78 percent in 2008.

Facebook: Head of the social class

CNBC's Jon Fortt reports on the social network's growing popularity as a new study shows that 73 percent of online adults are now members of a social network.

Of the top social networks for recruiting, 94 percent of recruiters said they used LinkedIn, followed by 65 percent for Facebook and 55 percent for Twitter.

Research firm Research and Markets said in a global recruitment report last month that job applicants are also increasingly using social media to network and identify employment opportunities.

"What we've seen is an increase in background checks. So a third party is hired to check everything - go through qualifications, check previous work history, check activities," said Andrew Tomich, executive general manager for recruitment firm Hudson Singapore, in response to a question about whether there was greater use of social media by employers to assess potential candidates.

"I think in some situations, organizations are using social media to assess someone. It's a big thing if you are in a public facing role," he added.

Indeed, what somebody says on social media can have ramifications for their current or future employment.

Justine Sacco was sacked as communications director of New-York based internet firm InterActive Corp last month after sending a tweet before departing on a holiday to South Africa that linked AIDS to race.

Speaking about privacy at The New York Times' Global Forum Asia last year, Meg Whitman, chief executive of computer giant Hewlett-Packard, had this to say on the subject:

"There has to be some personal responsibility here. When you put things on the internet, on Facebook, on Twitter on LinkedIn, you have to assume that it's almost like standing outside your house with a sign – handing out your information – you have to be really thoughtful about what you put online."

"Companies have a real responsibility to take that data that is near and dear to you, and handle it in a really thoughtful, deliberate way, and use all resources to maintain that privacy," she added.